alamb commented on code in PR #15348:
URL: https://github.com/apache/datafusion/pull/15348#discussion_r2010872746
##########
datafusion/physical-plan/src/sorts/cursor.rs:
##########
@@ -294,16 +294,44 @@ impl CursorValues for StringViewArray {
}
fn eq(l: &Self, l_idx: usize, r: &Self, r_idx: usize) -> bool {
+ // SAFETY: Both l_idx and r_idx are guaranteed to be within bounds,
+ // and any null-checks are handled in the outer layers.
+ // Fast path: Compare the lengths (or a proxy of the lengths) before
full byte comparison.
+
+ let l_view = unsafe { l.views().get_unchecked(l_idx) };
+ let l_len = *l_view as u32;
+ let r_view = unsafe { r.views().get_unchecked(r_idx) };
+ let r_len = *r_view as u32;
+ if l_len != r_len {
+ return false;
+ }
+
unsafe { GenericByteViewArray::compare_unchecked(l, l_idx, r,
r_idx).is_eq() }
}
fn eq_to_previous(cursor: &Self, idx: usize) -> bool {
+ // SAFETY: The caller guarantees that idx > 0 and the indices are
valid.
+ // Fast path: Compare the lengths of the current and previous views.
+
+ assert!(idx > 0);
+ let l_view = unsafe { cursor.views().get_unchecked(idx) };
+ let l_len = *l_view as u32;
+ let r_view = unsafe { cursor.views().get_unchecked(idx - 1) };
+ let r_len = *r_view as u32;
+ if l_len != r_len {
+ return false;
+ }
+
unsafe {
GenericByteViewArray::compare_unchecked(cursor, idx, cursor, idx -
1).is_eq()
}
}
fn compare(l: &Self, l_idx: usize, r: &Self, r_idx: usize) -> Ordering {
+ // SAFETY: Prior assertions guarantee that l_idx and r_idx are valid
indices.
+ // Null-checks are assumed to have been handled in the wrapper (e.g.,
ArrayValues).
+ assert!(l_idx < l.len());
Review Comment:
`assert`s are left in release builds of rust.
##########
datafusion/physical-plan/src/sorts/cursor.rs:
##########
@@ -294,16 +294,44 @@ impl CursorValues for StringViewArray {
}
fn eq(l: &Self, l_idx: usize, r: &Self, r_idx: usize) -> bool {
+ // SAFETY: Both l_idx and r_idx are guaranteed to be within bounds,
+ // and any null-checks are handled in the outer layers.
+ // Fast path: Compare the lengths (or a proxy of the lengths) before
full byte comparison.
Review Comment:
👍
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